SIOUX FALLS, S.D. (AP) – Oglala Sioux tribal officials want federal authorities to reopen investigations into 16 more unresolved deaths and disappearances at a South Dakota reservation, including one dating back nearly 50 years, a lawyer for the tribe said.

Jennifer Baker said tribal officials intend to present the list of names to U.S. Attorney Brendan Johnson during a meeting in Rapid City on Wednesday and that the list adds to the 28 deaths on or around the Pine Ridge Indian Reservation that Johnson agreed to re-examine nearly a month ago. Baker gave the latest list to The Associated Press ahead of that meeting and those names haven’t otherwise been made public.

As with the first list, the majority of cases to be presented are from the 1970s, when the murder rate on the reservation was the highest in the nation and tension between the American Indian Movement and federal authorities was high.

But the new list broadens the scope of the requested investigations by several decades by including the 1964 death of Delbert T. Yellow Wolf, the oldest case presented for re-examination so far, and the 2010 death of Samantha One Horn. One person on the list is missing but has not been declared dead.

Johnson didn’t immediately respond to a call for comment Wednesday. He said last month that he does not want to get anyone’s hopes up that unresolved cases might be solved or prosecuted, but that he hopes that with the new attention on the cases, more people may come forward with new evidence or leads.

Baker, a Colorado-based lawyer, said tribal leaders expanded the original list – presented in May – after uncovering new information. Further details on the cases were not made available.

The FBI typically investigates murders on reservations while the U.S. Attorney prosecutes the cases.

The original list contained 28 cases that Oglala Sioux officials wanted reopened because they said the FBI hadn’t sufficiently investigated them. Eleven more cases resulted in prosecutions, but the tribe believed those prosecuted “were inadequately charged and/or received insufficient sentences.”

Baker acknowledged that further prosecution on the allegedly under-prosecuted cases was unlikely because the American judicial system doesn’t allow for suspects to be tried twice for the same crime.

Last month, Johnson announced that three attorneys from his office would be assigned to review the case files from the first list of names. But because many of the cases occurred during a violent period of the 1970s, Johnson said it would likely be challenging to gather new evidence.

Tom Poor Bear, the tribe’s vice president, said the requests for new investigations stem from tribe members’ “lack of trust in the FBI.”

“I would like to see a special team of investigators other than the FBI come down and investigate these deaths,” he told the AP in June. He didn’t immediately return a phone call from the AP on Wednesday.

The original list includes the deaths of Poor Bear’s brother, Wilson Black Elk, and cousin, Ron Hard Heart, whose bodies were found in 1999 on reservation land across the border from Whiteclay, Neb.

One reopened case has been successfully prosecuted.

American Indian Movement activist Annie Mae Aquash’s 1975 killing went unsolved for decades until Fritz Arlo Looking Cloud was convicted of first-degree murder in 2004 in federal court. John Graham was convicted in state court for the death in 2010.

The FBI in 2000 issued a report detailing their investigations into the deaths of 57 people that occurred during the 1970s. The report said the bureau was right in closing the cases, even in situations where no one had been prosecuted for a death deemed unnatural.